11891911609 has 2 divisors, whose sum is σ = 11891911610. Its totient is φ = 11891911608.

The previous prime is 11891911601. The next prime is 11891911613. The reversal of 11891911609 is 90611919811.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 11289700009 + 602211600 = 106253^2 + 24540^2 .

It is a cyclic number.

It is not a de Polignac number, because 11891911609 - 2³ = 11891911601 is a prime.

It is not a weakly prime, because it can be changed into another prime (11891911601) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5945955804 + 5945955805.

It is an arithmetic number, because the mean of its divisors is an integer number (5945955805).

Almost surely, 2^11891911609 is an apocalyptic number.

It is an amenable number.

11891911609 is a deficient number, since it is larger than the sum of its proper divisors (1).

11891911609 is an equidigital number, since it uses as much as digits as its factorization.

11891911609 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 34992, while the sum is 46.

The spelling of 11891911609 in words is "eleven billion, eight hundred ninety-one million, nine hundred eleven thousand, six hundred nine".